1. Field of the Invention
The invention is related to the field of magnetic recording disk drive systems and, in particular, to methods for fabricating perpendicular write heads with a controlled separation region providing spacing between a write pole and a shield of a write head.
2. Statement of the Problem
Magnetic hard disk drive systems typically include a magnetic disk, a recording head having write and read elements, a suspension arm, and an actuator arm. As the magnetic disk is rotated, air adjacent to the disk surface moves with the disk. This allows the recording head (also referred to as a slider) to fly on an extremely thin cushion of air, generally referred to as an air bearing. When the recording head flies on the air bearing, the actuator arm swings the suspension arm to place the recording head over selected circular tracks on the rotating magnetic disk where signal fields are written to and read by the write and read elements, respectively. The write and read elements are connected to processing circuitry that operates according to a computer program to implement write and read functions.
The increasing demand for higher areal density has caused a scaling of the recording head structure to smaller dimensions. In perpendicular recording devices, the distance separating the write pole and the wrap around shield needs to be accurately defined for optimal performance of the write pole. If the wrap around shield is placed too close to the write pole, then flux from the write pole is absorbed by the wrap around shield instead of being transmitted to the recording media. On the other hand, if the wrap around shield is placed too far away from the write pole, then the wrap around shield is ineffective. Thus, flux may be transmitted to adjacent bits of the recording media during the writing process, potentially corrupting the data of the adjacent bits. Present fabrication processes are ineffective for accurately defining the separation distance between the write pole and the wrap around shield. Thus, it is a problem for fabricating write heads providing optimal write performance.
Additionally, in longitudinal recording devices, the stripe height of the read sensor is an important parameter defined by lapping. The stripe height is controlled by electronic lapping guides (ELGs) which are aligned with the read sensor, or by the sensor resistance itself. When the read sensor resistance value reaches a target value, the lapping process is stopped.
By contrast, in perpendicular recording devices, critical elements defined by lapping now exist both in the read and write heads. For the write head, the placement of the flare point of the write pole and the back-edge of the shields are important to proper operation. Present lapping techniques are ineffective for simultaneously defining both the read and write elements within tight lapping tolerances. Thus, it is also a problem to accurately align elements of the recording head within the tight tolerances needed for optimal performance of the recording head.